The present invention relates to an endoscopic treatment instrument, and in particular to a component of the endoscopic treatment instrument.
FIG. 32 shows the distal end portion of an endoscopic biopsy forceps which is one of the most commonly used endoscopic treatment instruments. A manipulating wire 2 is passed through a flexible sheath 1 to be capable of moving back and forth along the longitudinal axis. A distal end support member 3 is attached to the distal end of the sheath 1, and a pair of forceps cups 7 are supported on the member 3 such that they can open or close about a support shaft 5 like beaks.
A groove 3a open toward the front end is formed in the front portion of the distal end support member 3. A drive mechanism 10 that is actuated by the manipulating wire 2 to drive the forceps cups 7 to open and close is held within the groove 3a. 
FIG. 33 shows the distal end support member 3 that is a component of the endoscopic treatment instrument. The rear portion 3A of the member 3 is formed like a tube into which the tip of the sheath 1 is to be inserted. The groove 3a into which the drive mechanism 10 is to be held is formed in the front portion 3B of the member 3.
To fabricate the distal end support member 3, a rod-shaped workpiece must be subjected to at least two cutting operations, one being drilling from the back and the other being the formation of a groove in the front portion. In addition, the use of a milling machine is required to increase the cost of component fabrication.
An object, therefore, of the invention is to provide a distal end support member for an endoscopic treatment instrument, which has a drive mechanism holding groove and a sheath connector and which can be manufactured at low-cost.
FIG. 14 shows a wire connecting link 90 which is connected to the distal end of the manipulating wire 2 as another component of the endoscopic treatment instrument. The link 90 has a mechanism connector 91 formed at one end and a wire holder 92 at the other end. The mechanism connector 91 has a hole 93 bored in a direction perpendicular to the longitudinal axis for establishing connection to the drive mechanism 10. The wire holder 92 has a hole 94 extending along the longitudinal axis into which the distal end of the manipulating wire 2 is inserted and fixed.
The manipulating wire 2 inserted into the hole 94 is silver brazed or otherwise fixed to the wire connecting link 90. Since brazing is effected at the mouth 94a of the hole 94, the wire holder 92 has a side hole 95 through which the operator can visually check if brazing material has flowed to the deepest part of the hole 94. The side hole 95 also functions to permit air to escape therethrough when the brazing material flows into the hole 94.
The provision of the side hole 95, however, has one serious problem. When a force is exerted on the wire connecting link 90 during service, the stress is concentrated around the side hole 95 to increase the chance of breaking of the link in areas near the side hole 95.
Another object, therefore, of the present invention is to provide a wire connecting link for an endoscopic treatment instrument, which makes it possible to positively check the state of the flow of a brazing material and which is durable because of the absence of any area where stress concentration occurs.
A wire connecting link according to a first aspect of the present invention includes a mechanism connector formed by flattening one end of a single tubular workpiece, and a wire holder formed by the rest of the tubular workpiece. This wire connecting link makes it possible to positively check the state of the flow of a brazing material during the brazing of a manipulating wire. This is realized without the provision of any area where stress concentration occurs, and therefore the wire connecting link is excellent in mechanical durability.
In an endoscopic treatment instrument of a preferred embodiment, a wire connecting link has a mechanism connector formed at one end for establishing connection to a mechanism member and a wire holder formed at the other end into which a manipulating wire is inserted and fixed. The wire connecting link is made from a single tubular workpiece which is flattened at one end to form the mechanism connector, the remaining tubular part forming the wire holder.
The tubular workpiece may be formed by bending or curving a sheet of workpiece into a tubular shape, with the resulting seam being left unclosed.
A distal end support member according to a second aspect of the invention includes a drive mechanism holding groove formed by bending a first strip of a metal blank in a U-shapem and a sheath connector formed by bending a second strip at right angles in a direction away from the first strip and then into an annular shape. The distal end support member does not require any cutting operations on a milling machine or the like, and can be fabricated mostly by press working. This contributes to a substantial reduction in the manufacturing cost and, hence, can realize the fabrication of disposable endoscopic treatment instruments that are effective in preventing inter-patient infection.
An endoscopic treatment instrument of a preferred embodiment has a distal end support member comprising a drive mechanism holding groove shaped in a U-form to hold a distal end treatment member drive mechanism in a movable fashion and a sheath connector shaped in an annular form to be capable of connection to the distal end of a sheath. A metal blank comprising a first strip and a second strip parallel thereto is deformed such that the first strip is bent in a U-shape to form the drive mechanism holding groove while the second strip is wholly bent at right angles in a direction away from the first strip and further bent in an annular shape to form the sheath connector.
The second strip may consist of two parts connecting to opposite sides of the first strip. If the first strip is formed to be thicker than the other parts of the blank, the resulting drive mechanism holding groove can have adequate mechanical strength.
The sheath connector may consist of two parts joined together in a single ring. The joining parts of the sheath connector may have interlocking portions that prevent them from slipping out of each other in a circumferential direction.
The end faces of the joining parts of the sheath connector may include a plurality of inclined surfaces that contact each other at an angle such that one joining part underlies the other joining part in a radial direction and that an area where one joining part underlies the other joining part alternates with an area where said one joining part overlies the other joining part.
The present disclosure relates to the subject matter contained in Japanese patent application Nos. Hei. 11-294683 (filed on Oct. 18, 1999) and Hei. 11-296086 (filed on Oct. 19, 1999), which are expressly incorporated herein by reference in their entireties.